Adjustable axle assemblies are commonly utilized to adjust wheel spacing in agricultural vehicles for numerous reasons including the accommodation of a variety of row spacings and the following of specified wheel track patterns. Examples of such structures are shown in U.S. Pat. Nos. 6,139,045; 5,454,583; and 5,282,644. Although various devices for determining and setting axle position have been available, providing repeatable and reliable wheel spacing adjustments in a user-friendly manner with adequate interlocks to assure adjustments are made only under proper operating conditions has been a continuing source of problems. Some systems require the operator to read indicia on or adjacent the adjustable axle and are inconvenient to use. Others require each axle assembly to be adjusted separately which is a time-consuming process on vehicles having numerous axle assemblies.